/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.tomcat.websocket.pojo;

import org.apache.tomcat.websocket.WsSession;

import javax.websocket.DecodeException;
import javax.websocket.MessageHandler;
import javax.websocket.Session;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * Common implementation code for the POJO whole message handlers. All the real
 * work is done in this class and in the superclass.
 *
 * @param <T> The type of message to handle
 */
public abstract class PojoMessageHandlerWholeBase<T>
		extends PojoMessageHandlerBase<T> implements MessageHandler.Whole<T> {

	public PojoMessageHandlerWholeBase(Object pojo, Method method,
	                                   Session session, Object[] params, int indexPayload,
	                                   boolean convert, int indexSession, long maxMessageSize) {
		super(pojo, method, session, params, indexPayload, convert,
				indexSession, maxMessageSize);
	}

	@Override
	public final void onMessage(T message) {

		if (params.length == 1 && params[0] instanceof DecodeException) {
			((WsSession) session).getLocal().onError(session,
					(DecodeException) params[0]);
			return;
		}

		// Can this message be decoded?
		Object payload;
		try {
			payload = decode(message);
		} catch (DecodeException de) {
			((WsSession) session).getLocal().onError(session, de);
			return;
		}

		if (payload == null) {
			// Not decoded. Convert if required.
			if (convert) {
				payload = convert(message);
			} else {
				payload = message;
			}
		}

		Object[] parameters = params.clone();
		if (indexSession != -1) {
			parameters[indexSession] = session;
		}
		parameters[indexPayload] = payload;

		Object result = null;
		try {
			result = method.invoke(pojo, parameters);
		} catch (IllegalAccessException e) {
			handlePojoMethodException(e);
		} catch (InvocationTargetException e) {
			handlePojoMethodException(e);
		}
		processResult(result);
	}

	protected Object convert(T message) {
		return message;
	}

	protected abstract Object decode(T message) throws DecodeException;

	protected abstract void onClose();
}
